Oops... problems with Firefox 2 installer
"There's a problem with the installer where it doesn't shut down Firefox completely and so files don't get updated. Uninstall Firefox 2.0, delete the application folder (on Windows, C:\Program Files\Mozilla Firefox), and reinstall. If they're still not there, read this. "
"Some Windows users are reporting that their bookmarks are missing after upgrading to Firefox 2. This problem is apparently related to the installer not properly exiting all Firefox processes (bug 357922). In this case, the bookmarks are not lost. To restore the "missing" bookmarks and fix other problems that may be related to the upgrade: Uninstall Firefox, delete the Firefox program folder (usually "C:\Program Files\Mozilla Firefox") and reinstall Firefox 2. The bookmarks will be back to normal (you may need to reinstall some added plugins). "